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Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1992
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
Test method according to OECD TG 301 C. No data on GLP.
Qualifier:
according to
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
GLP compliance:
not specified
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
- Concentration of sludge: 30 mg/L
Duration of test (contact time):
28 d
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
TOC removal
Key result
Parameter:
other: BOD (NO2)
Value:
20
Sampling time:
28 d
Key result
Parameter:
other: BOD (NH3)
Value:
26
Sampling time:
28 d
Key result
Parameter:
% degradation (TOC removal)
Value:
28
Sampling time:
28 d

The test substance was hydrolyzed to form 2-Butanone oxime(2-0546, persistence, Low-Bioconcentration), Monomethylsilanol, and polymer (Polysiloxane) of the Monomethylsilanol. Analysis of the test substance was difficult.

Degradation % results were:

Indirect analysis

BOD (NO2)

BOD (NH3)

28, 9, 24

36, 12, 31

 

Direct analysis

TOC

34, 20, 31

 

Validity criteria fulfilled:
not specified
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The test substance butan-2-one O,O',O''-(methylsilylidyne)trioxime was determined to be not readily biodegradable under test conditions.
Executive summary:

The readily biodegradation test was performed by MITI according to OECD Guideline 301 C. 30 mg/L of activated sludge were exposed for 28 days to 100 mg/L of test item butan-2-one O,O',O''-(methylsilylidyne)trioxime. The biodegradation was analysed by indirect analysis, BOD (NO2) and BOD (NH3) obtaining a biodegradation of 20% and 26% respectively and by direct TOC analysis obtaining a biodegradation of 28%. The test substance was determined to be not readily biodegradable under test conditions.

The test substance was hydrolyzed to form 2-Butanone oxime (2-0546, persistence, Low-Bioconcentration), Monomethylsilanol, and polymer (Polysiloxane) of the Monomethylsilanol. Analysis of the test substance was difficult.

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
(Q)SAR
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Remarks:
Internationally accepted method, EPI-Suite, EPA (USA)
Justification for type of information:
See attached the QMRF and QPRF for the QSAR model.
Principles of method if other than guideline:
Calculation by EPI-Suite, EPA (USA) / BIOWIN v4.10
GLP compliance:
no

The substances butan-2-one O,O',O''-(vinylsilanetriyl)oxime is predicted not to be readily biodegradable by EPI-Suite, EPA (USA) / BIOWIN v4.10.

Validity criteria fulfilled:
not applicable
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The substances butan-2-one O,O',O''-(vinylsilanetriyl)oxime is predicted not to be readily biodegradable by EPI-Suite, EPA (USA) / BIOWIN v4.10 calculation method.
Executive summary:

The substances butan-2-one O,O',O''-(vinylsilanetriyl)oxime is predicted not to be readily biodegradable by EPI-Suite, EPA (USA) / BIOWIN v4.10 calculation method.

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
The analogue Butan-2-one O,O',O''-(methylsilanetriyl)oxime which shares the same functional group with Butan-2-one O,O',O''-(vinylsilanetriyl)oxime, also has comparable values for the relevant molecular properties for biodegradation.
See attached the reporting format.
Reason / purpose:
read-across source
Key result
Parameter:
other: BOD (NO2)
Value:
20
Sampling time:
28 d
Remarks on result:
other: (Results based on analogue substance butan-2-one O,O',O''-(methylsilanetriyl)oxime)
Key result
Parameter:
other: (NH3)
Value:
26
Sampling time:
28 d
Remarks on result:
other: (Results based on analogue substance butan-2-one O,O',O''-(methylsilanetriyl)oxime)
Key result
Parameter:
% degradation (TOC removal)
Value:
28
Sampling time:
28 d
Remarks on result:
other: (Results based on analogue substance butan-2-one O,O',O''-(methylsilanetriyl)oxime)
Details on results:
The analogue substance butan-2-one O,O',O''-(methylsilanetriyl)oxime was hydrolyzed to form 2-Butanone oxime(2-0546, persistence, Low-Bioconcentration), Monomethylsilanol, and polymer (Polysiloxane) of the Monomethylsilanol. Analysis of the test substance was difficult. Based on these results the test item butan-2-one O,O',O''-(vinylsilanetriyl)oxime is also expected to hydrolyse to form 2-butanoe oxime and the corresponding silanol and polysiloxane.
Validity criteria fulfilled:
not specified
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
Based on the read-across approach from experimental results on analogue substance butan-2-one O,O',O''-(methylsilylidyne)trioxime, the test item butan-2-one O,O',O''-(vinylsilylidyne)trioxime was determined to be not readily biodegradable.
Executive summary:

The readily biodegradation test was performed by MITI according to OECD Guideline 301 C on analogue substance butan-2-one O,O',O''-(methylsilylidyne)trioxime. 30 mg/L of activated sludge were exposed for 28 days to 100 mg/L. The biodegradation was analysed by indirect analysis, BOD (NO2) and BOD (NH3) obtaining a biodegradation of 20% and 26% respectively and by direct TOC analysis obtaining a biodegradation of 28%. Based on these results, the read-across was applied and the test item butan-2-one O,O',O''-(vinylsilylidyne)trioxime was determined to be not readily biodegradable under test conditions.

Description of key information

Key study: Based on the read-across approach from experimental results (test method OECD 301C) on the analogue substance butan-2-one O,O',O''-(methylsilylidyne)trioxime, butan-2-one O,O',O''-(vinylsilylidyne)trioxime was determined to be not readily biodegradable.

Supporting study: EPI-Suite v4.1 (BIOWIN): Butan-2-one O,O',O''-(vinylsilanetriyl)oxime was predicted to not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Key study: Read-across from experimental data on analogue butan-2-one O,O',O''-(methylsilanetriyl)oxime:

A readily biodegradation test was performed by MITI according to OECD Guideline 301 C on analogue substance butan-2-one O,O',O''-(methylsilylidyne)trioxime. 30 mg/L of activated sludge were exposed for 28 days to 100 mg/L. The biodegradation was analysed by indirect analysis, BOD (NO2) and BOD (NH3) obtaining a biodegradation of 20% and 26% respectively and by direct TOC analysis obtaining a biodegradation of 28%. Based on these results, the read-across was applied and the test item butan-2-one O,O',O''-(vinylsilylidyne)trioxime was determined to be not readily biodegradable under test conditions.

Supporting study: According the the calculation method EPI-Suite, EPA (USA) / BIOWIN v4.10, butan-2-one O,O',O''-(vinylsilanetriyl)oxime was predicted to not readily biodegradable.